During the past year studies have concentrated on the production of broadly reacting antibody in mice, utilizing the principal of original antigenic sin (OAS). Antibody was produced in BALB/c mice by first priming them with purified gp120 from the LAV strain of HIV conjugated to KLH, followed by serial immunization with CEM cells optimally infected with four wildly divergent strains of HIV-I. These included the delta U mutant clone of PNL4-3, p Alabama 15.3, RZ-34 MC, and wild-type Z84. Not only did these animals develop reactivity in the ELISA and RIP tests against gp120 (titers 1:60 -> 1:1920), they developed neutralizing antibody (titers 1:240 -> 1:1920) against the various strains to which they were exposed. In addition, they developed neutralizing antibody against the NYS strain of HIV (1:20 -> 1:120) to which they had not been immunized. To date, one animal has been sacrificed and its spleen cells fused to P-3 myeloma cells. Approximately ten primary clones were picked and, after secondary cloning, four clones remain which demonstrate specific reactivity.